Aerated lagoons, ponds or tanks, hereinafter referred to generally as water treatment basins, are commonly used as a part of an overall water treatment system. Such water treatment basins generally utilize diffusion type aerators or mechanical aerators. ln diffusion type aerators, air or oxygen is introduced into the water under pressure through submerged diffusers or nozzles. Mechanical type aerators generally agitate the water so as to promote solution of air from the atmosphere into the water.
Mixers are sometimes employed in the water treatment basins to maintain solids in suspension and to improve distribution of oxygen in the basin. However, the water in some water treatment basins, due to industrial chemicals and/or fertilizers from runoff, tends to foam. Since mixers are generally arranged to draw water from adjacent the surface of the basin and pump it downwardly toward the bottom of the water treatment basin in order to maintain the solids in suspension and improve distribution of the aerated water in the basin, the mixers tend to draw the foam on the surface of the basin toward the mixers. Foam levels have been encountered in some water treatment basins that are so high that they cover the mixer and mixer motor and problems have been encountered in overheating and burn out of the mixer motors.